This is a prospective study of hyperglycemia and diabetes mellitus in a population. Persons with postprandial blood sugar values above the Oxford, Mass., population's ninety-second percentile will be re-examined in 1973-74, some 27 to 28 years later, as well as an age-stratified sample of persons with blood sugars below this level. In addition, the complete 17 to 38 year segment of the original 1946-47 study will be re-examined. The health risks of the whole range of blood sugars will be determined by documenting the presence of cardiovascular and renal disease, and diabetes mellitus in this follow-up examination with due consideration for other important variables such as age and sex. The prevalence of diabetes in the population segment aged 17 to 38 years, and now aged 44 to 65 years, will be compared with the prevalence of diabetes among persons 44 to 65 years in 1946 for evidence of an increase in the prevalence of this disease over the past quarter of a century.